[n] the principal character in a work of fiction
[n] a person who backs a politician or a team etc.; "all their supporters came out for the game"; "they are friends of the library"
admirer - (3 syllables), booster - (2 syllables), champion - (3 syllables), friend - (1 syllables), supporter - (3 syllables)
advocate, advocator, anglophil, anglophile, antihero, believer, Boswell, character, Confederate, convert, endorser, enthusiast, exponent, fictional character, fictitious character, Francophil, Francophile, free trader, functionalist, Graecophile, Jacobite, loyalist, mainstay, maintainer, New Dealer, partisan, partizan, philhellene, philhellenist, pillar, proponent, ratifier, Roundhead, seconder, Shavian, stalwart, subscriber, sustainer, sympathiser, sympathizer, toaster, truster, upholder, verifier, voucher, wassailer, well-wisher, Whig
\Pro*tag"o*nist\, n. [Gr. ?; prw^tos first + ? an actor, combatant, fr. ? a contest.] One who takes the leading part in a drama; hence, one who takes lead in some great scene, enterprise, conflict, or the like. Shakespeare, the protagonist on the great of modern poetry. --De Quincey.